Machine-switching telephone system



Nov. 18, 1924. 1,515,735

c. GOODRUM ET AL MACHINE SWITCHING TELEPHONE SYSTEM Filed July 21 1921 2Sheets-Sheei Nov. 18, 1924. 1,515,735

' c. L. GOODRUM ET AL MACHINE SWITGHE NG TELEPHONE SYSTEM Filed July 21.1921 2 Sheets-Sheet 2 &

Patented Nov. 18, 1924.

UNITED STATES PATENT OFFICE.

CHARLES L. GOODRUM, OF NEW YORK, N. Y., AND JOHN N. REYNOLDS, OFGREENWICH,

CONNECTICUT, ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEWYORK, N. Y., A. CORPORATION OF NEW YOR MACHINE-SWITCHING TELEPHONESYSTEM.

Application filed July 21, 1921.

To all whom it may concern.

Be it known that we, CHARLES L. Goon- RUM and JOHN N. REYNOLDS, citizensof the United States, residing at New York, in

the county of New York, State of New York, and Greenwich, in the countyof F airfield, State of Connecticut, respectively, have invented certainnew and useful Improvements in Machine-Switching Telephone Systems,

of which the following is a full, clear, concise, and exact description.

This invention relates to a coordinate switch particularly useful inautomatic telephone circuits, and especially to a unitary coordinateswitch wherein an array of individually operable switching devices isemployed for connecting incoming and outgoing lines.

An object of the invention is to provide,

in such a unitary switch, a wiring arrangement whereby any number ofcoexisting connections may be established by a common operating member.

This is accomplished by providing for the array of individually operableswitches, which may be arranged in longitudinal and transverse rows,selecting mechanism which includes a common controlling element for theswitches of each row, each longitudinal row being divided into sectionsserving separate and distinct line circuits, respectively.

More specifically, the invention relates to a switch of the typedescribed which contains link circuits for connection between incomingand outgoing lines, whereby a plurality of coexisting line-link-lineconnections may be established with the economy of operation notedabove.

A further feature of the invention is the provision, in such a unitaryswitch, of a wiring arrangement whereby interference betweensimultaneously calling incoming lines is prevented and the possibilityof double connections between incoming lines and lines accessiblethereto is obviated.

This is accomplished by providing operating circuits for the series ofcontrolling elements serving incoming lines which are dependent fortheir continuity upon contacts controlled by other controlling elementsof the series in such a manner that the operation of one controllingelement renders the Serial No. 486,442.

operating circuits of the remaining controlling elements temporarilyineffective.

In addition to the features above outlined such other features andadvantages as are contemplated by the present invention will be clearlyunderstood from the description given hereafter and from the appendedclaims.

The invention is shown in two figures, Fig. 1 of which is a circuitarrangement and Fig. 2 is a perspective view of one type of mechanicalapparatus, which may be employed in such a circuit arrangement.

There are in the art a variety of mechanical switching structuresinvolving cooperating switching members, each member controlling aplurality of circuit making con tacts, which might be used in the systemof this invention. An example of these numerous switching structures isshown in the patent to Roberts No. 1,143,998, issued June 22, 1915. Thepreferred form of switching mechanism for employment in a system of thischaracter, which is shown in Fi 2 of the drawing, was devised by J. N.eynolds and is disclosed in the British patent to \Vestern ElectricCompany, Ltd., No. 183,436, accepted August 23, 1923.

Considering first Fig. 2, the operation is as follows:

It is desired to establish a connection between the group of conductors1, 2, 3 and 4 and the group of conductors 5, 6, 7 and 8. Conductor 5 ismultipled at several points to spring wires such as 9 and 10; conductor6 is multipled in the same manner to spring wires 11 and 12; conductor 7is multiplied to spring wires 13 and 14, and conductor 8 is multipled tospring wires 15 and 16. Thus each group of conductors, such asconductors 5, 6, 7 and 8, are multipled to the movable contact setsforming a vertical row.

Associated with the group of conductors 5, 6, 7 and 8 is a magnet 17which controls an armature 18 to rotate a bar or switching member 19.Secured to this bar and associated with each roup of spring wires suchas 9, 11, 13 an 15 and 10, 12, 14 and 16, are spring arms 20 and 21,respectively. When the magnet 17 is energized, all of the spring arms,such as 20 and 21, are moved in a clockwise direction through therotation of bar 19.

Associated with the group of -conductors 1, 2, 3 and 4 isa. magnet 22which, through an armature 23, controls a switching member or bar 24.Secured to this bar and associated with each group of conductors similarto the group 5, 6, 7 and 8 are arms such as 25 and 26. After the magnet17 has become operated and the spring wire arm 21 has moved in aposition above the arm 26, the ma et 22 may be operated whereupon thespring arm 21 will be moved upwardly. Each of the arms, such as 25 and26, contains a notch 27 which is for the purpose of preventing thespring arm 21 from slipping when the magnet 17 is deen'ergized to returnall of the spring arms, such as 20, back to their normal positions,leaving only the one, 21, in an operated position.

Associated with each group of spring wires, such as the group 9, 11, 13and 15 and the group 10, 12, 14 and '16, is a piece of insulatingmaterial, such as hard rubber or fiber 28 and 29. The spring wires 10,12, 14 and 16 project through slots cut in the insulating material 29.This insulating piece is so fashioned at its lower end that when thespring 21 has been moved in a clockwise direction and the arm 26 hasbeen rotated upwardly, spring 21 will move the insulating piece 29bodily upward, bringing the spring wires 10, 12, 14 and 16 into contactwith conductors 1, 2, 3 and 4, respectively.

For holding the piece of insulating material 29 in position, two springs30 and 31 are rovided which are threaded through the insu ating materialand bent over in a manner to locate the piece 29. The spring wire 31after being threaded through the insulation is also bent upwardly andthen outwardly so that when the group of spring wires 10, 12, 14 and 1.6are at rest, they will be preventel from moving downwardly a suflicientdistance to contact with. the conductors of the group 1, 2, 3 and 4.

It will be seen from this arrangement that, if two magnets 17 and 32 aresimultaneouilcy energized and then magnet 22 is energiz a connectionwill be established from conductor 5 to conductor 1 and thence toconductor 33 and in the same manner conductors 6, 7 and 8 will beconnected through conductors 2, 3 and 4 to conductors 34, 35 and 36. Thegroup of spring wires, together with the conductors with which theycooperate, thus forms a field of switches arranged in vertical orlongitudinal rows and horizontal or transverse rows, which collectivelymay be considered a switchboard.

Considering now the circuit arrangement shown in Fig. 1, the operationis as follows:

There are shown two groups of three incoming lines each, the upper groupcontaining lines 37, 38 and 39 and the lower group containing lines 40,41 and 42.

Let it be assumed that the subscriber on line 39 wishes to establish aconnection. The circuits in Fig. 1 show how upon the removal of thereceiver on the line 39, it will be automatically connected to trunk 43.

A calling subscriber on line 39 removing his receiver from theswitchhook establishes a circuit for the energization of the line relay44. This circuit extends from ground, left-hand winding of relay 44,back contact and outer left-hand armature of cut-0E relay 45, over theclosed loop of line 39, the inner left-hand armature and back contact ofcut-oil relay 45, right-hand windingof line relay 44, to battery andground. This establishes a circuit from ground, the lefthand armatureand back contact of link magnet 22, the front contact and innerrighthand armature of relay 44, winding of magnet 17, to battery andground. Magnet 17 rotates the line bar 19 and prepares to move theinsulating piece 29, or any of the others shown on the vertical lineabove the magnet 17, Fig. 1. The insulating piece 29 controls theconnection of line 39 to the first link 1, 2, 3 serving this subgroup oflines and insulating piece 28 controls the connection of said line tothe second link. While only two links per subgroup are shown, anydesired number may be provided and the first idle one is utilized.Magnet 17 in attracting its armatures closes a circuit from ground,inner right-hand armature and front contact of magnet 17, back contactand inner left-hand armature of slow releasing relay 46, winding oftrunk bar magnet 32, to battery and ground. This magnet 32 causes therotation of a bar similar to 19 and prepares for the operation of theinsulating pieces 47 48, 49 and 50 common to the trunk 43 andrespectively individual to the several links. Magnet 32 in attractingits armatures locks itself in a circuit from ground, inner right-handarmature and front contact of magnet 17, left hand armature and frontcontact of magnet 32, outer armature and contact of relay 51, winding ofmagnet 32, to battery and ound. This locking circuit is necessaryficause upon the energization of magnet 32 a circuit is established fromground, inner right-hand armature and front contact of magnet 32,winding of slow releasing relay 46, to battery and ground, causing theenergization of this latter relay and the opening of the originalenergizing circuit of magnet 32. Magnet 32 also closes a circuit fromground, the outer right-hand armature and front contact of magnet 32,left-hand armature and front contact of magnet 17 the outer right-handarmature and back contact of relay. 59, the outer right-hand armatureand front contact of line relay 44, the normal contact of the innerright-hand armature of magnet 22, winding of magnet 22, to battery andground, assumin the first link 1, 2, 3 serving the group 0 lines 37, 38,3-9, etc. to be idle. Magnet 22 becomes energized in this circuit and bymeans of the arms 26 and 25 causes the movement of insulating pieces 29and 49, whereupon a circuit is established from conductors 5, 6, 7 and 8through the link conductors 1, 2, 3 and 4, respectively, to trunkconductors 33, 34, 35 and 36, respectively. A circuit is now establishedfrom ground, front contact and right-hand armature of relay 46,conductor 35, conductor 3, alternate contact of the right-hand armatureof magnet 22, winding of magnet 22, to battery and ground and inparallel therewith through conductor 7, winding of cut-01f relay 45, tobattery and ground. Magnet 22 is locked in this circuit and relay 45 isenergized in this circuit. Cut-off relay 45 becoming energized opens thecircuit for line relay 44 which retracts its armatures and opens thecircuitfor magnet 17 and magnet 17 opens the original energizing circuitof magnet 32. Magnet 17 deenergizes provided no other line served by theswitching bar 19 is calling at th1s time. Simultaneously with theenergization of cutofl relay 45, which is as soon as the line 39 isextended to trunk 43, a circuit through the windings of relay 51 iscompleted over the loop of the substation and this relay remainsenergized during the establishment of the connection. Relay 51 opens thelocking circuit of magnet 32 so that if magnet 17 has not becomedeenergized by thls time magnet 32 will be restored and will release itsassociated switching bar. Relay 51 also maintains relay 46 energized byplacing a ground on the winding of relay 46 as a substitute for theground placed there by the inner right-hand armature of magnet 32. Theconnection between the line and trunk is maintained by the continuedenergization of magnet 22 which controls the link bar 24.

When the subscriber on line 39 replaces his receiver on the switchhookand opens the loop of this line, relay 51 becomes deenergized andshortly thereafter relay 46 retracts its armatures, removing ground fromconductor 35 and allowing magnet 22 and relay 45 to become deenergizedwhereupon the connections are restored to normal.

When the magnet 22 is energized, say in one connection, the starter wirefrom the front contact and outer right-hand armature of relay 44 isextended through the front contact and outer right-hand armature ofmagnet 22 to the link bar magnet 55, so that another call coming in, sayfrom line 37 or 38, may be extended over the link circuit shown justabove the one c'omprising conductors 1, 2, 3 and 4.

While trunk 43 is busy,

relay 46 is energized so that a second call initiated in any subgroup oflines will seize trunk 56 through a circuit extending through theleft-hand armature and back contact of magnet 32, the outer left-handarmature and front contact of relay 46, the back contact and innerleft-hand armature of relay 58, Winding of magnet 57, to battery andground.

Certain general features of this system which should be pointed out areas follows: First, the lines in a vertical or longitudinal row abovemagnet 17 form one digital subgroup, and second, the lines in ahorizontal or transverse row to the right of magnet 22 form anotherdigital subgroup.

These two subgroups may be said to be in the two principal directions ofa twocoordinate systetm and hence in a one hundred line main group,there will be twenty digital subgroups, ten of which will be characterized by the tens digit and the remaining ten will be characterizedby the units digit.

It is not, of course, actual number of the lines be placed in anyparticular order, the above described grouping being arranged throughthe connections of the contacts and armatures of the line relays.

All of the link circuits trunks such as 43 and 56. The link circuitsare, however, divided into groups and each group of link circuits isindividual to a particular group of lines in one direction of thetwo-coordinate system. Thus, the group of link circuits comprisingconductors 1, 2, 3 and 4 is individual to the particular subgroups oflines 37, 38 and 39 and forms a row of contact sets, one before eachline and trunk bar. It should be noted that each of these links isavailable to each of these lines and the same is true of other linkswith respect to the lines of their r spective groups.

It should be noted that the subgroup magnets are not rendered individualthrough the act of establishing a connection. The magnet 17, forinstance, after assisting in the extension of line 39, through a linkcircuit comprising conductors 1, 2, 3 and 4 to trunk 43, may thereafterassist in the extension of line 42 or in the extension of anycorresponding line in other subgroups.

It should be further noted that magnet 17, upon energizing, opens itsouter right-hand armature contacts and removes battery potential fromthe windings of all other magnets corresponding to magnet 17, such asmagnets 61, 62, etc., serving other lines of the same or othersubgroups, as, for example, lines 37, 38, 40 and 41. so that should acall be simultaneously initiated upon other lines served b such othermagnets, no interference will result and the possibility of doubleconnections to the same link circuit necessary that the have access tothe is obviated. Similarly, the remaining magnets 61, 62, etc.disconnect battery potential from all other magnets succeeding them inorder in such a manner that it is not possible for two such magnets toremain energized at the same time, the magnet nearest the source ofpotential being given the preference.

Should two lines in difierent subgroups, for example, lines 39 and 42,both served by the same magnet 17, call simultaneously, the connectionof both lines to the same trunk circuit through diiierent link circuitsis prevented since it is not possible for link bar magnets, such as 22and 60, serving, respectively, the subgroups of lines in which lines 39and 42 terminate to become simultaneously operated. The circuit for themagnet 22 is open at this time at the back contact of the'line relay 59of line l2 and cannot be closed until after line 42 has'become extendedto a trunk line and line relay 59 is released.

What is claimed is:

1. The combination in a switching system of incoming circuits, linkcircuits, out goin circuits, ,contact sets, a plurality of switc ingbars movable independently of and cooperating with each other foractuating said contact sets to connect an incoming circuit to a linkcircuit and to connect such link circuit to any outgoint circuit, andmeans for maintaining the established con nection with a single one ofsaid bars.

2. The combination in a switching system of line circuits, linkcircuits, trunk circuits, contact sets, line bars serving said lines,link bars serving said links, a trunk bar for each of said trunks, saidbars being movable independently of said contact sets, means for causingthe joint operation of a line bar, a link bar and a trunk bar, said barscooperating with each other for actuating said contact sets to connect aline to a link and to connect such link to a trunk, and means wherebythe link bar maintains the established connection.

3. The combination of a switching system of line circuits, linkcircuits, trunk circuits, contact sets, line bars serving said lines,link bars serving said links, a trunk bar for each of said trunks, meansfor causing the joint operation of a line bar, a link bar and a trunkbar, said bars cooperating with each other for actuating said contactsets to connect a line to a link and to connect such link to a trunk,means for releasing the line and trunk bars, and means controlled by thelink bar for maintaininlg1 the established connection,

4. e combination in a switching system of lines divided into sub-groups,a group of links for each sub-group of lines, trunks serving all of saidlinks, line switching members each serving a line in each subgroup, linkswitching members individual to said links, trunk switching membersindividual to said trunks, and means for causing the joint operation ofone of each of said switching members to connect a line to a link and toconnect such link to a trunk.

5. In a switching system, a plurality of link circuits, a plurality oflines intersecting all of said link circuits, a second plurality oflines severally arranged to intersect a portion only of said linkcircuits, switching means at each point of intersection, the switchingmeans at each point of intersection being operable independently ofparticular switching means at other points of intersec tion, and meansfor operating said switching means in pairs whereby a line of one groupis connected, to a line of the other group through one of said linkcircuits.

6. The combination in a switching system of a plurality of sets ofcontacts arranged in a row and divided into groups, a plurality ofincoming lines, each connected in multiple to the sets of contactscomprising one of said groups, another plurality of sets of contactsarranged in rows, a plurality of outgoing lines, each connected inmultiple to the sets of contacts comprising one of said other rows, aplurality of sets of link conductors, each associated individually witha set of contacts of said first mentioned row and with a set of contactsin each of said last mentioned rows, and means operable to establish aconnection between a set of contacts associated with one of saidincoming lines and its associated set of link conductors andsimultaneously operable to establish a connection between a set ofcontacts associated with one of said outgoing lines and said set of linkconductors.

7. The combination in a switching system of incoming lines, outgoinglines, contact sets for said incoming lines, contact sets for saidoutgoing lines, an operating mechanism common to said incoming lines, anoperating mechanism individual to each outgoing line, other operatingmechanisms associated in common with said first and second mentionedoperating mechanisms, the conjoint operation of one of each of saidfirst, second and third mentioned operating mechanisms being effectiveto actuate the contact sets of said incoming and outgoing lines toestablish a connection between one of said incoming and one of saidoutgoing lines, said first mentioned operating mechanism being operablein conjunction with other of said second and third operating mechanismsto establish connections between other incoming and outgoing linescoexisting with the connection a ready established.

8. In a telephone system, a. group of lines grraaigied on abtwocoordinate bafsis 2111;

ivieintosu u,a upotru for serving said li d sfli nk cii c uits forinterconnecting said lines and said trunks, said link circuits beingdivided into groups. each group of link circuits being individual to asubgroup of said lines in one coordinate direction, independentlyoperable contact arrangements each for connecting one of said lines toone of said links, independently operable contact arrangements each forconnecting one of said links to one of said trunks, and means forsimultaneously operating a plurality of said contact arrangements toextend one of said lines to any one of said trunks.

9. In a switchboard, the con'ibination with conductors for two groups oflines, one group divided into subgroups, of a plurality of connectinglinks each provided with a plurality of switches comprising one switchfor a line in each of said subgroups of one of the groups of lines andone for each of the lines of the other group. and mechanism for thecommon control of all the switches and adapted to operate the saidswitches of any connecting link in pairs independently of the conditionof the switches of all other connecting links, said mechanism includingthree cooperating sets of elements, one set for the selection of linesby subgroups in one of said groups of lines. another set for theselection of individual lines in the other group, and the third set forthe selection of individual connecting links.

10. In a switchboard, the combination of line conductors, a plurality ofconnecting links, each provided with one switch for the conductors ofone line in each of several subgroups of one group of lines and oneswitch for the conductors of each line of another group, and mechanismfor the common control of all the switches and adapted to 0 erate onepair of said switches after anot er in the several connecting links,said mechanism including three cooperating sets of elements, one set forthe individual selection of subgroups in one of said groups of lines,another set for the individual selection of lines in the other group,and the third set for the individual selection of connecting links.

11. In a switchboard, the combination of a group of line conductorsarranged in subgroups, link oonductors forming with said line conductorsan array of independently operable switches divided into switching setseach inclusive of one line circuit only in each of the subgroups thereofand collectively adapted to establish interchangeable connections forthe said line conductors to the connecting links, and mechanism ada tedto operate the switches individually includin two cooperating sets ofmembers, each 0 one set for the common control of all switches servinga. subgroup of line conductors and each of the other set for the commoncontrol of all switches of a switching set.

12. In a switchboard, the combination with conductors for two groups oflines one group divided into subgroups. of a plurality of connectinglinks collectively adapted to establish and maintain a plurality ofindependent connections between the lines of one group and the lines ofanother group. each such connecting link being provided with one switchfor one line in each of several subgroups of one of said groups of linesand one switch for each of the lines in the other group. and mechanismfor the common control of all the switches and adapted to actuate andrelease successivel v one pair of said switches after another in severalconnecting links and to hold the actuated switches in operationsimultaneously, each such operation for any pair of switches in anyconnecting link being independent of the condition of the switches inall other connecting links. said mechanism including three cooperatingsets of elements, one set for the individual selection of lines bysubgroups in one of said groups of lines and adapted to condition foroperation the switches associated with any such selected subgroup.another set for the individual selection of lines in the other group andadapted to condition for operation the switches associated with any suchselected line, and the third set for the individual selection ofconnecting links and adapted to operate the particular pair of saidswitches of any such selected link which in each instance is conditionedfor operation by the other two sets of elements.

13. A switchboard having rows of contacts forming terminals for onegroup of lines greater in number than said rows. other rows of contactsforming terminals for another group of lines equal in number to the lastmentioned rows, connecting links crossing all of said rows and formingwith each of said contacts a switching point, and controlling mechanismincluding a. designating element common to a plurality of lines in the ufirst mentioned group for each row and a holding element for eachconnecting link, whereby upon the joint operation of two dosignatingelements and a holding element any line of one group may be extended toany line of the other.

14. In a switchboard, the combination with a field of switches arrangedin longitudinal and transverse rows and mechanism adapted to operate anyof said switches individually. including two cooperating sets ofmembers. each of one set for the common control of all switches in alongitudinal row and each of the other set for the common control of allswitches in a transverse row. of line conductors arranged in alongitudinal row and extending to separate ortions, respectively, of oneof said longitu inal rows of switches. and link conductors each 1extending to one of said transverse rows of m switches whereby the lineconductors may be successively selected and separately connected toaccessible link conductors.

15. In a switchboard, the combination with a field of switches arrangedin longitudinal and transverse rows and mechanism adapted to operate anyof said switches individually. including two cooperating sets ofmembers. each of one set forthe common control of all switches in alongitudinal row and each of the other set for the common control of allswitches in a transverse row. of a series of line conductors arranged ina longitudinal row and leading to separate portions, respectively. ofone of said longitudinal rows of switches. a single line conductorleading to another of said longitudinal rows of switches. and linkconductors each leading to one of said transverse rows of switcheswhereby any line conductor in sa d series may be selected and connectedto said smgle line conductor through a link conductor accessible toboth.

16. A coordinate switch having rows of contacts forming terminals of onegroup of lines greater in number than said rows. other rows of contactsforming terminals of another group of lines equal in number to the lastmentioned rows. connecting links r'or all of said rows and forming witheach of said contacts an individually operable switch ng point. andcontrolling mechanism includ ng a line member common to the switchingpoints of each row. and a link member for each connecting link wherebyupon the joint operation of a pair of line members and a selected linkmember any line of one group may be extended to any line of the other17. In a switchboard. the combmation of an array of individuallyoperable switches arranged in longitudinal and transverse rows, andselecting mechanism including a common controlling element for theswitches in each row, each longitudinal row being divided into sectionsfor separate line circuits respectively. and each transverse rowcomprising a connecting group.

18. In a switchboard. the combination with an array of individuallyoperable switches arranged in longitudinal and transverse rows andselecting mechanism including a common controlling element for theswitches of each row. of conductors for separate line circuits leadingto different switches. respectively, of each longitudinal row and a linkcircuit conductor joining the switches of each transverse row into aconnecting group.

19. In a switchboard. the combination of an array of-individuallyoperable switches arranged in longitudinal and transverse rows. eachlongitudinal row comprising a plurality of sections for a correspondingplurality of separate line circuits, an individual line circuitconductor leading to each section of each longitudinal row of switches,an individual link circuit conductor joining the switches of eachtransverse row and forming therewith a connecting group, and selectingmechanism including a common controlling element for the switches ineach row.

20. The combination in a switching system of incoming lines. linkcircuits and outgoing lines, with means for establishing linelink-lineconnections comprising a set of incoming line bars. a set of link barsand a set of outgoing line bars. and means for preventing thesimultaneous operation of more than one bar of each of said sets.

21. The combination in a switching system of incoming lines, linkcircuits and outgoing lines. with means under the control of incominglines for establishing line-link-line connections comprising a set ofincoming line bars. a set of link bars and a set of outgoing line bars.and means to prevent interference between simultaneously callingincoming lines.

22. The combination in a switching system of incoming lines. linkcircuits and outgoing lines, with means for establishing line-linklineconnections comprising a set of incoming line bars, a set of link bars,a set of outgoing line bars, operating magnets for said bars, saidmagnets having armature contacts and operating circuits for the magnetscorresponding to the bars of one of said sets and dependent for theircontinuity upon said contacts. a

23. The combination in a switching system of lines, circuits therefor,contact sets, a set of switching bars, a second set of switching bars,the bars of one set cooperating with the bars of the other set forconnecting any line to any circuit, a series of operating magnets foreach set of switching bars, said magnets having armature contacts, andan operating circuit for each of the magnets of one of said series, theoperating circuit for each of the magnets of said series, except thefirst, extending through the contacts controlled by all precedingmagnets in said series whereby the simultaneous opera tion of theswitching bars of one of said sets is prevented.

24. A selector having rows of contacts multiply connected in groupsnumerically greater than said rows, other rows of contactsmultiplyconnected in groups numerically equal to said other rows, linkscrossing all of said rows and forming with said contacts an individuallyoperable switching device at each said crossing point, and controllingmechanism com risin condi tioning elements associated with sai rowsinnllI operating elements associated with said in s.

25. In a. telephone system, primary lines arranged in coordinate groups,a line magnet for the lines of each grouo in one coordinate direction, aplurality of link magnets for each group of lines in another coordinatedirection, a link circuit controlled by each of said last magnets, aplurality of secondary lines accessible to said link circuits, asecondary line magnet for each of said secondary lines, means forestablishing a connection between a primary and a secondary line byinitially energizing a primary line magnet and a secondary line magnetand thereafter an idle one of said link magnets, and means formaintaining said established connection by deenergizing said primary andsecondary line magnets and maintaining said link magnet energized.

' 26. A selector having coordinately arranged individually operableswitching points, mechanical means for operating said points andelectrical means for controlling said mechanical means, said electricalmeans comprising a magnet for each row of points in one coordinatedirection, said magnets being divided into groups, a circuit arrangementfor selectively operating the magnets of one group and for automaticallyoperating the magnets of another group, a magnet for each row of pointsin another coordinate direction. said last mentioned magnets beingdirided into groups and a circuit arrangement for selecting a group andautomatically operating the'magnets of said selected group.

27. In combination in a switching unit, rows of line and link contactscoordinately arranged, a single controlling element for each line row, asingle controlling element for each link row, said line and linkcontrolling elements cooperating to effect engagement between line andlink contacts common to the intersecting line and link rows, :1 group ofincoming lines, a group of outgoing lines, some of the lines of\one ofsaid groups appearing in a greater number of link rows than any line ofthe other group and each link row serving to connect a line in one groupto any one of a plurality of lines in the other group.

In witness whereof, we hereunto subscribe our names this 20th day ofJuly A. D., 1921.

CHARLES L. GOODRUM. JOHN N. REYNOLDS.

DISCLAIMER.

1,515,735.-0harles L. Goodrum, New York, N. Y., and John N. Reynolds,Greenwich, Conn. MACHINE Swrrcnmc TELEPHONE SYSTEM. Patent datedNovember 18, 1924. Disclaimer filed February 8, 1927, by the paten-tees,assignee; Western Electric Company, Incorporated. consenting.

Hereby enter this disclaimer to the said claims of said Letters Patentwhich are in the followin words, to wit:

7. The com ination in a switching system of incoming lines, outgoinglines, contact sets for said incoming lines. contact sets for saidoutgoing lines, an operating mechanism common to said incoming; lines.an operatin; mechanism individual to each outgoing line. other operatingmechanisn'is associated in common with said first and second mentionedoperatingmechanisms, the conjoint operation of one of each of saidfirst, second and third mentioned operating mechanisms being effectiveto actuate the contact sets of said incoming and outgoing lines toestablish a connection between one of said incoming and one of saidoutgoing lines. said first mentioned operating mechanism being operablein conjunction with other of said second and third operatingimechanismsto establish connections between other incoming and outgoing linesco-existing with the connection already established.

20. The combination in a switching! system of incoming lines, linkcircuits and outgoing lines, with means for establishing line-link-lineconnections comprising a set of incoming line bars, a et of link barsand a 'set of outgoing line bars, and

means for preventing the simultaneous operation of more than one bar ofeach of said sets.

21. The combination in a switching system of incoming lines, linkcircuits and outgoing lines, with means under the control of incominglines for establishing linelink-line connections comprising set ofincoming line bars, a set of link bars and a set of outgoing line bars,and means to prevent interference between simultaneousl calling incominlines.

[ ffim'al Gazette limb. 1, 1927.]

